Toolbar "Cascade As Menu" vs MMB PopUp - Can't have it all?

Is it a bug if I can’t have the Toolbar option “Cascade As Menu” while also having my pop-up toolbar work as intended? My Pop-Up just flashes on and off at this point.

Not sure how long it’s been like this. Just doing some housecleaning, and ticked the Cascade As Menu for the first time in a while.

Thanks

Alan